Re: Blockbusting news, results get worse

John Bradford
2003-10-27T20:01:26Z

Quote from Jeff Garzik <jgarzik@pobox.com>:
> Hans Reiser wrote:
> > Mudama, Eric wrote:
> >
> >>
> >> or put it under heavy write workload and remove
> >> power.
> >>
> > Can you tell us more about what really happens to disk drives when the
> > power is cut while a block is being written? We engage in a lot of
> > uninformed speculation, and it would be nice if someone who really knows
> > told us....
> >
> > Do drives have enough capacitance under normal conditions to finish
> > writing the block? Does ECC on the drive detect that the block was bad
> > and so we don't need to detect it in the FS?
>
>
> Does it really matter to speculate about this?
>
> If you don't FLUSH CACHE, you have no guarantees your data is on the
> platter.

I think that the idea that is floating around is to deliberately ruin
the formatting on part of the drive in order to simulate a bad block.

Operation of disk drives immediately after a power failiure has been
discussed before, by the way:

http://marc.theaimsgroup.com/?l=linux-kernel&m=100665153518652&w=2

John.